How to destructuring array when change value new array but old array not change

Question

var a = [{a: '1'}, {a: '2'}, {a: '3'}];

var b = [...a];

b[0].a = 2;

console.log(a)

// result expect is b = [{a: '1'}, {a: '2'}, {a: '3'}];

// but real result is b = [{a: '2'}, {a: '2'}, {a: '3'}];

score 1 · Answer 1 · answered Sep 12 '18 at 17:27

1

You have to recreate all items in the new Array:

var b = a.map(i => { return { ...i } })

answered Sep 12 '18 at 17:27

np42

thanks too much ^^! – vân tang Sep 12 '18 at 17:30
Why not `var b = JSON.parse(JSON.stringify(a));`? Doesn't look like OP has functions inside `a`. – connexo Sep 12 '18 at 17:50
It works too, maybe more costly, lose some values (undefined, function, RegExp, Date, ...) but go deeper – np42 Sep 12 '18 at 17:52

1 Answers1